Feedback for a system information request

ABSTRACT

Apparatuses, methods, and systems are disclosed for sending and/or receiving feedback for a system information request. One apparatus includes a transmitter that transmits information indicating a request for system information. The apparatus includes a processor that monitors, during a predetermined time period, for a feedback response indicating that the request for the system information was received.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 15/464,086filed on Mar. 20, 2017, which is hereby incorporated by reference in itsentirety.

FIELD

The subject matter disclosed herein relates generally to wirelesscommunications and more particularly relates to feedback for a systeminformation request.

BACKGROUND

The following abbreviations are herewith defined, at least some of whichare referred to within the following description: Third GenerationPartnership Project (“3GPP”), Positive-Acknowledgment (“ACK”), BinaryPhase Shift Keying (“BPSK”), Clear Channel Assessment (“CCA”), CyclicPrefix (“CP”), Channel State Information (“CSI”), Common Search Space(“CSS”), Discrete Fourier Transform Spread (“DFTS”), Downlink ControlInformation (“DCI”), Downlink (“DL”), Downlink Pilot Time Slot(“DwPTS”), Enhanced Clear Channel Assessment (“eCCA”), Enhanced MobileBroadband (“eMBB”), Evolved Node B (“eNB”), European TelecommunicationsStandards Institute (“ETSI”), Frame Based Equipment (“FBE”), FrequencyDivision Duplex (“FDD”), Frequency Division Multiple Access (“FDMA”),Guard Period (“GP”), Hybrid Automatic Repeat Request (“HARQ”),Internet-of-Things (“IoT”), Licensed Assisted Access (“LAA”), Load BasedEquipment (“LBE”), Listen-Before-Talk (“LBT”), Long Term Evolution(“LTE”), Multiple Access (“MA”), Modulation Coding Scheme (“MCS”),Machine Type Communication (“MTC”), Multiple Input Multiple Output(“MIMO”), Multi User Shared Access (“MUSA”), Narrowband (“NB”),Negative-Acknowledgment (“NACK”) or (“NAK”), Next Generation Node B(“gNB”), Non-Orthogonal Multiple Access (“NOMA”), Orthogonal FrequencyDivision Multiplexing (“OFDM”), Primary Cell (“PCell”), PhysicalBroadcast Channel (“PBCH”), Physical Downlink Control Channel (“PDCCH”),Physical Downlink Shared Channel (“PDSCH”), Pattern Division MultipleAccess (“PDMA”), Physical Hybrid ARQ Indicator Channel (“PHICH”),Physical Random Access Channel (“PRACH”), Physical Resource Block(“PRB”), Physical Uplink Control Channel (“PUCCH”), Physical UplinkShared Channel (“PUSCH”), Quality of Service (“QoS”), Quadrature PhaseShift Keying (“QPSK”), Radio Resource Control (“RRC”), Random AccessProcedure (“RACH”), Random Access Response (“RAR”), Reference Signal(“RS”), Resource Spread Multiple Access (“RSMA”), Round Trip Time(“RTT”), Receive (“RX”), Sparse Code Multiple Access (“SCMA”),Scheduling Request (“SR”), Single Carrier Frequency Division MultipleAccess (“SC-FDMA”), Secondary Cell (“SCell”), Shared Channel (“SCH”),Signal-to-Interference-Plus-Noise Ratio (“SINR”), System InformationBlock (“SIB”), Transport Block (“TB”), Transport Block Size (“TBS”),Time-Division Duplex (“TDD”), Time Division Multiplex (“TDM”),Transmission Time Interval (“TTI”), Transmit (“TX”), Uplink ControlInformation (“UCI”), User Entity/Equipment (Mobile Terminal) (“UE”),Uplink (“UL”), Universal Mobile Telecommunications System (“UMTS”),Uplink Pilot Time Slot (“UpPTS”), Ultra-reliability and Low-latencyCommunications (“URLLC”), and Worldwide Interoperability for MicrowaveAccess (“WiMAX”). As used herein, “HARQ-ACK” may represent collectivelythe Positive Acknowledge (“ACK”) and the Negative Acknowledge (“NAK”).ACK means that a TB is correctly received while NAK means a TB iserroneously received.

In certain wireless communications networks, some system information maybe transmitted and/or received more often than is necessary. In certainconfigurations, to reduce the signaling load for providing systeminformation, a minimum amount of system information may be used. Theminimum system information (“SI”) may contain basic information forinitial access to the cell (e.g., subframe number, list of public landmobile networks (“PLMNs”), cell camping parameters, RACH parameters)that is broadcast periodically in a cell. In some configurations, theother non-minimum SI doesn't necessarily need to be periodicallybroadcast (e.g., it may be a network decision). In variousconfigurations, the other SI may be provided on-demand to UEs (e.g., aUE may request it). Delivery of other SI may be done in a broadcast orunicast manner. In some configurations, the minimum SI may indicatewhether a specific SIB is periodically broadcasted or providedon-demand. To obtain the one or more SIBs which are not periodicallybroadcasted and are provided on-demand, a UE may initiate an on-demandSI acquisition procedure (e.g., SI request). For an SI used by the UE,the UE may determine whether it is available in the cell and whether itis broadcast or not before it sends a request for it. The schedulinginformation for other SI may be provided by the minimum SI (e.g., an SIBtype, validity information, periodicity, SI-window information, etc.).

In various configurations, a UE may not be aware whether an SI requestis correctly detected by a gNB and may unnecessarily monitor during theSI window for the delivery of the requested SI. Accordingly, a UEbattery may drain unnecessarily and there may be an increase in latencyfor the SI provisioning.

BRIEF SUMMARY

Apparatuses for transmitting and/or receiving feedback for a systeminformation request are disclosed. Methods and systems also perform thefunctions of the apparatus. In one embodiment, the apparatus includes atransmitter that transmits information indicating a request for systeminformation. In certain embodiments, the apparatus includes a processorthat monitors, during a predetermined time period, for a feedbackresponse indicating that the request for the system information wasreceived.

In one embodiment, the apparatus includes a receiver that receivesscheduling information corresponding to the system information. In afurther embodiment, in response to receiving the feedback response, thereceiver receives the system information based on the schedulinginformation. In certain embodiments, in response to not receiving thefeedback response: the transmitter retransmits information indicatingthe request for the system information; and the processor monitors,during the predetermined time period, for the feedback responseindicating that the request for the system information was received. Invarious embodiments, the transmitter retransmits the information usingincreased power. In some embodiments, the transmitter repeatsretransmitting information indicating the request for the systeminformation up to a predetermined number of times.

In certain embodiments, the feedback response is part of downlinkcontrol information. In some embodiments, a radio network temporaryidentifier is used to indicate the feedback response. In variousembodiments, the feedback response is indicated by one or more fields ofdownlink control information set to one or more predefined values. Inone embodiment, the feedback response is part of a random accessresponse message transmitted on a physical downlink shared channel. Incertain embodiments, the information indicating the request for thesystem information includes a physical random access channel preamble.

In some embodiments, the feedback response includes a physical randomaccess channel preamble identifier corresponding to the physical randomaccess channel preamble. In various embodiments, the informationindicating the request for the system information is part of a message 3transmission during random access. In certain embodiments, theinformation indicating the request for the system information includes abitmap indicating the requested system information. In one embodiment,the feedback response includes information indicating the requestedsystem information. In some embodiments, the feedback response is partof a contention resolution message during random access. In variousembodiments, downlink scheduling information for the system informationis transmitted with the feedback response.

A method for receiving feedback for a system information request, in oneembodiment, includes transmitting information indicating a request forsystem information. In various embodiments, the method includesmonitoring, during a predetermined time period, for a feedback responseindicating that the request for the system information was received.

In one embodiment, an apparatus includes a receiver that receivesinformation indicating a request for system information. In variousembodiments, the apparatus includes a transmitter that transmits afeedback response indicating that the request for the system informationwas received.

In one embodiment, the transmitter transmits scheduling informationcorresponding to the system information. In a further embodiment, thetransmitter transmits the system information based on the schedulinginformation. In certain embodiments, the feedback response is part ofdownlink control information. In some embodiments, a radio networktemporary identifier is used to indicate the feedback response. Invarious embodiments, the feedback response is indicated by one or morefields of downlink control information set to one or more predefinedvalues. In one embodiment, the feedback response is part of a randomaccess response message transmitted on a physical downlink sharedchannel. In certain embodiments, the information indicating the requestfor the system information includes a physical random access channelpreamble.

In some embodiments, the feedback response includes a physical randomaccess channel preamble identifier corresponding to the physical randomaccess channel preamble. In various embodiments, the informationindicating the request for the system information is part of a message 3transmission during random access. In certain embodiments, theinformation indicating the request for the system information includes abitmap indicating the requested system information. In one embodiment,the feedback response includes information indicating the requestedsystem information. In some embodiments, the feedback response is partof a contention resolution message during random access. In variousembodiments, downlink scheduling information for the system informationis transmitted with the feedback response.

A method for transmitting feedback for a system information request, inone embodiment, includes receiving information indicating a request forsystem information. In some embodiments, the method includestransmitting a feedback response indicating that the request for thesystem information was received.

BRIEF DESCRIPTION OF THE DRAWINGS

A more particular description of the embodiments briefly described abovewill be rendered by reference to specific embodiments that areillustrated in the appended drawings. Understanding that these drawingsdepict only some embodiments and are not therefore to be considered tobe limiting of scope, the embodiments will be described and explainedwith additional specificity and detail through the use of theaccompanying drawings, in which:

FIG. 1 is a schematic block diagram illustrating one embodiment of awireless communication system for transmitting and/or receiving feedbackfor a system information request;

FIG. 2 is a schematic block diagram illustrating one embodiment of anapparatus that may be used for receiving feedback for a systeminformation request;

FIG. 3 is a schematic block diagram illustrating one embodiment of anapparatus that may be used for transmitting feedback for a systeminformation request;

FIG. 4 illustrates one embodiment of communications for transmitting andreceiving feedback for a system information request;

FIG. 5 illustrates another embodiment of communications for transmittingand receiving feedback for a system information request;

FIG. 6 is a schematic flow chart diagram illustrating one embodiment ofa method for receiving feedback for a system information request; and

FIG. 7 is a schematic flow chart diagram illustrating one embodiment ofa method for transmitting feedback for a system information request.

DETAILED DESCRIPTION

As will be appreciated by one skilled in the art, aspects of theembodiments may be embodied as a system, apparatus, method, or programproduct. Accordingly, embodiments may take the form of an entirelyhardware embodiment, an entirely software embodiment (includingfirmware, resident software, micro-code, etc.) or an embodimentcombining software and hardware aspects that may all generally bereferred to herein as a “circuit,” “module” or “system.” Furthermore,embodiments may take the form of a program product embodied in one ormore computer readable storage devices storing machine readable code,computer readable code, and/or program code, referred hereafter as code.The storage devices may be tangible, non-transitory, and/ornon-transmission. The storage devices may not embody signals. In acertain embodiment, the storage devices only employ signals foraccessing code.

Certain of the functional units described in this specification may belabeled as modules, in order to more particularly emphasize theirimplementation independence. For example, a module may be implemented asa hardware circuit comprising custom very-large-scale integration(“VLSI”) circuits or gate arrays, off-the-shelf semiconductors such aslogic chips, transistors, or other discrete components. A module mayalso be implemented in programmable hardware devices such as fieldprogrammable gate arrays, programmable array logic, programmable logicdevices or the like.

Modules may also be implemented in code and/or software for execution byvarious types of processors. An identified module of code may, forinstance, include one or more physical or logical blocks of executablecode which may, for instance, be organized as an object, procedure, orfunction. Nevertheless, the executables of an identified module need notbe physically located together, but may include disparate instructionsstored in different locations which, when joined logically together,include the module and achieve the stated purpose for the module.

Indeed, a module of code may be a single instruction, or manyinstructions, and may even be distributed over several different codesegments, among different programs, and across several memory devices.Similarly, operational data may be identified and illustrated hereinwithin modules, and may be embodied in any suitable form and organizedwithin any suitable type of data structure. The operational data may becollected as a single data set, or may be distributed over differentlocations including over different computer readable storage devices.Where a module or portions of a module are implemented in software, thesoftware portions are stored on one or more computer readable storagedevices.

Any combination of one or more computer readable medium may be utilized.The computer readable medium may be a computer readable storage medium.The computer readable storage medium may be a storage device storing thecode. The storage device may be, for example, but not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, holographic,micromechanical, or semiconductor system, apparatus, or device, or anysuitable combination of the foregoing.

More specific examples (a non-exhaustive list) of the storage devicewould include the following: an electrical connection having one or morewires, a portable computer diskette, a hard disk, a random access memory(“RAM”), a read-only memory (“ROM”), an erasable programmable read-onlymemory (“EPROM” or Flash memory), a portable compact disc read-onlymemory (“CD-ROM”), an optical storage device, a magnetic storage device,or any suitable combination of the foregoing. In the context of thisdocument, a computer readable storage medium may be any tangible mediumthat can contain, or store a program for use by or in connection with aninstruction execution system, apparatus, or device.

Code for carrying out operations for embodiments may be any number oflines and may be written in any combination of one or more programminglanguages including an object oriented programming language such asPython, Ruby, Java, Smalltalk, C++, or the like, and conventionalprocedural programming languages, such as the “C” programming language,or the like, and/or machine languages such as assembly languages. Thecode may execute entirely on the user's computer, partly on the user'scomputer, as a stand-alone software package, partly on the user'scomputer and partly on a remote computer or entirely on the remotecomputer or server. In the latter scenario, the remote computer may beconnected to the user's computer through any type of network, includinga local area network (“LAN”) or a wide area network (“WAN”), or theconnection may be made to an external computer (for example, through theInternet using an Internet Service Provider).

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment. Thus, appearances of the phrases“in one embodiment,” “in an embodiment,” and similar language throughoutthis specification may, but do not necessarily, all refer to the sameembodiment, but mean “one or more but not all embodiments” unlessexpressly specified otherwise. The terms “including,” “comprising,”“having,” and variations thereof mean “including but not limited to,”unless expressly specified otherwise. An enumerated listing of itemsdoes not imply that any or all of the items are mutually exclusive,unless expressly specified otherwise. The terms “a,” “an,” and “the”also refer to “one or more” unless expressly specified otherwise.

Furthermore, the described features, structures, or characteristics ofthe embodiments may be combined in any suitable manner. In the followingdescription, numerous specific details are provided, such as examples ofprogramming, software modules, user selections, network transactions,database queries, database structures, hardware modules, hardwarecircuits, hardware chips, etc., to provide a thorough understanding ofembodiments. One skilled in the relevant art will recognize, however,that embodiments may be practiced without one or more of the specificdetails, or with other methods, components, materials, and so forth. Inother instances, well-known structures, materials, or operations are notshown or described in detail to avoid obscuring aspects of anembodiment.

Aspects of the embodiments are described below with reference toschematic flowchart diagrams and/or schematic block diagrams of methods,apparatuses, systems, and program products according to embodiments. Itwill be understood that each block of the schematic flowchart diagramsand/or schematic block diagrams, and combinations of blocks in theschematic flowchart diagrams and/or schematic block diagrams, can beimplemented by code. The code may be provided to a processor of ageneral purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the functions/acts specified in the schematic flowchartdiagrams and/or schematic block diagrams block or blocks.

The code may also be stored in a storage device that can direct acomputer, other programmable data processing apparatus, or other devicesto function in a particular manner, such that the instructions stored inthe storage device produce an article of manufacture includinginstructions which implement the function/act specified in the schematicflowchart diagrams and/or schematic block diagrams block or blocks.

The code may also be loaded onto a computer, other programmable dataprocessing apparatus, or other devices to cause a series of operationalsteps to be performed on the computer, other programmable apparatus orother devices to produce a computer implemented process such that thecode which execute on the computer or other programmable apparatusprovide processes for implementing the functions/acts specified in theflowchart and/or block diagram block or blocks.

The schematic flowchart diagrams and/or schematic block diagrams in theFigures illustrate the architecture, functionality, and operation ofpossible implementations of apparatuses, systems, methods and programproducts according to various embodiments. In this regard, each block inthe schematic flowchart diagrams and/or schematic block diagrams mayrepresent a module, segment, or portion of code, which includes one ormore executable instructions of the code for implementing the specifiedlogical function(s).

It should also be noted that, in some alternative implementations, thefunctions noted in the block may occur out of the order noted in theFigures. For example, two blocks shown in succession may, in fact, beexecuted substantially concurrently, or the blocks may sometimes beexecuted in the reverse order, depending upon the functionalityinvolved. Other steps and methods may be conceived that are equivalentin function, logic, or effect to one or more blocks, or portionsthereof, of the illustrated Figures.

Although various arrow types and line types may be employed in theflowchart and/or block diagrams, they are understood not to limit thescope of the corresponding embodiments. Indeed, some arrows or otherconnectors may be used to indicate only the logical flow of the depictedembodiment. For instance, an arrow may indicate a waiting or monitoringperiod of unspecified duration between enumerated steps of the depictedembodiment. It will also be noted that each block of the block diagramsand/or flowchart diagrams, and combinations of blocks in the blockdiagrams and/or flowchart diagrams, can be implemented by specialpurpose hardware-based systems that perform the specified functions oracts, or combinations of special purpose hardware and code.

The description of elements in each figure may refer to elements ofproceeding figures. Like numbers refer to like elements in all figures,including alternate embodiments of like elements.

FIG. 1 depicts an embodiment of a wireless communication system 100 fortransmitting and/or receiving feedback for a system information request.In one embodiment, the wireless communication system 100 includes remoteunits 102 and base units 104. Even though a specific number of remoteunits 102 and base units 104 are depicted in FIG. 1, one of skill in theart will recognize that any number of remote units 102 and base units104 may be included in the wireless communication system 100.

In one embodiment, the remote units 102 may include computing devices,such as desktop computers, laptop computers, personal digital assistants(“PDAs”), tablet computers, smart phones, smart televisions (e.g.,televisions connected to the Internet), set-top boxes, game consoles,security systems (including security cameras), vehicle on-boardcomputers, network devices (e.g., routers, switches, modems), or thelike. In some embodiments, the remote units 102 include wearabledevices, such as smart watches, fitness bands, optical head-mounteddisplays, or the like. Moreover, the remote units 102 may be referred toas subscriber units, mobiles, mobile stations, users, terminals, mobileterminals, fixed terminals, subscriber stations, UE, user terminals, adevice, or by other terminology used in the art. The remote units 102may communicate directly with one or more of the base units 104 via ULcommunication signals.

The base units 104 may be distributed over a geographic region. Incertain embodiments, a base unit 104 may also be referred to as anaccess point, an access terminal, a base, a base station, a Node-B, aneNB, a gNB, a Home Node-B, a relay node, a device, or by any otherterminology used in the art. The base units 104 are generally part of aradio access network that includes one or more controllers communicablycoupled to one or more corresponding base units 104. The radio accessnetwork is generally communicably coupled to one or more core networks,which may be coupled to other networks, like the Internet and publicswitched telephone networks, among other networks. These and otherelements of radio access and core networks are not illustrated but arewell known generally by those having ordinary skill in the art.

In one implementation, the wireless communication system 100 iscompliant with the LTE protocols standardized in 3GPP, wherein the baseunit 104 transmits using an OFDM modulation scheme on the DL and theremote units 102 transmit on the UL using a SC-FDMA scheme or an OFDMscheme. More generally, however, the wireless communication system 100may implement some other open or proprietary communication protocol, forexample, WiMAX, among other protocols. The present disclosure is notintended to be limited to the implementation of any particular wirelesscommunication system architecture or protocol.

The base units 104 may serve a number of remote units 102 within aserving area, for example, a cell or a cell sector via a wirelesscommunication link. The base units 104 transmit DL communication signalsto serve the remote units 102 in the time, frequency, and/or spatialdomain.

In one embodiment, a base unit 104 may receive information indicating arequest for system information from the remote unit 102. In certainembodiments, the base unit 104 may transmit to the remote unit 102 afeedback response indicating that the request for the system informationwas received. Accordingly, a base unit 104 may be used for transmittingfeedback for a system information request.

In another embodiment, a remote unit 102 may transmit informationindicating a request for system information. The remote unit 102 maymonitor, during a predetermined time period, for a feedback responseindicating that the request for the system information was received.Accordingly, a remote unit 102 may be used for receiving feedback for asystem information request.

FIG. 2 depicts one embodiment of an apparatus 200 that may be used forreceiving feedback for a system information request. The apparatus 200includes one embodiment of the remote unit 102. Furthermore, the remoteunit 102 may include a processor 202, a memory 204, an input device 206,a display 208, a transmitter 210, and a receiver 212. In someembodiments, the input device 206 and the display 208 are combined intoa single device, such as a touchscreen. In certain embodiments, theremote unit 102 may not include any input device 206 and/or display 208.In various embodiments, the remote unit 102 may include one or more ofthe processor 202, the memory 204, the transmitter 210, and the receiver212, and may not include the input device 206 and/or the display 208.

The processor 202, in one embodiment, may include any known controllercapable of executing computer-readable instructions and/or capable ofperforming logical operations. For example, the processor 202 may be amicrocontroller, a microprocessor, a central processing unit (“CPU”), agraphics processing unit (“GPU”), an auxiliary processing unit, a fieldprogrammable gate array (“FPGA”), or similar programmable controller. Insome embodiments, the processor 202 executes instructions stored in thememory 204 to perform the methods and routines described herein. Invarious embodiments, the processor 202 monitors, during a predeterminedtime period, for a feedback response indicating that a request forsystem information was received. The processor 202 is communicativelycoupled to the memory 204, the input device 206, the display 208, thetransmitter 210, and the receiver 212.

The memory 204, in one embodiment, is a computer readable storagemedium. In some embodiments, the memory 204 includes volatile computerstorage media. For example, the memory 204 may include a RAM, includingdynamic RAM (“DRAM”), synchronous dynamic RAM (“SDRAM”), and/or staticRAM (“SRAM”). In some embodiments, the memory 204 includes non-volatilecomputer storage media. For example, the memory 204 may include a harddisk drive, a flash memory, or any other suitable non-volatile computerstorage device. In some embodiments, the memory 204 includes bothvolatile and non-volatile computer storage media. In some embodiments,the memory 204 stores data relating to system information. In someembodiments, the memory 204 also stores program code and related data,such as an operating system or other controller algorithms operating onthe remote unit 102.

The input device 206, in one embodiment, may include any known computerinput device including a touch panel, a button, a keyboard, a stylus, amicrophone, or the like. In some embodiments, the input device 206 maybe integrated with the display 208, for example, as a touchscreen orsimilar touch-sensitive display. In some embodiments, the input device206 includes a touchscreen such that text may be input using a virtualkeyboard displayed on the touchscreen and/or by handwriting on thetouchscreen. In some embodiments, the input device 206 includes two ormore different devices, such as a keyboard and a touch panel.

The display 208, in one embodiment, may include any known electronicallycontrollable display or display device. The display 208 may be designedto output visual, audible, and/or haptic signals. In some embodiments,the display 208 includes an electronic display capable of outputtingvisual data to a user. For example, the display 208 may include, but isnot limited to, an LCD display, an LED display, an OLED display, aprojector, or similar display device capable of outputting images, text,or the like to a user. As another, non-limiting, example, the display208 may include a wearable display such as a smart watch, smart glasses,a heads-up display, or the like. Further, the display 208 may be acomponent of a smart phone, a personal digital assistant, a television,a table computer, a notebook (laptop) computer, a personal computer, avehicle dashboard, or the like.

In certain embodiments, the display 208 includes one or more speakersfor producing sound. For example, the display 208 may produce an audiblealert or notification (e.g., a beep or chime). In some embodiments, thedisplay 208 includes one or more haptic devices for producingvibrations, motion, or other haptic feedback. In some embodiments, allor portions of the display 208 may be integrated with the input device206. For example, the input device 206 and display 208 may form atouchscreen or similar touch-sensitive display. In other embodiments,the display 208 may be located near the input device 206.

The transmitter 210 is used to provide UL communication signals to thebase unit 104 and the receiver 212 is used to receive DL communicationsignals from the base unit 104. In various embodiments, the transmitter210 may be used to transmit information indicating a request for systeminformation. Although only one transmitter 210 and one receiver 212 areillustrated, the remote unit 102 may have any suitable number oftransmitters 210 and receivers 212. The transmitter 210 and the receiver212 may be any suitable type of transmitters and receivers. In oneembodiment, the transmitter 210 and the receiver 212 may be part of atransceiver.

FIG. 3 depicts one embodiment of an apparatus 300 that may be used fortransmitting feedback for a system information request. The apparatus300 includes one embodiment of the base unit 104. Furthermore, the baseunit 104 may include a processor 302, a memory 304, an input device 306,a display 308, a transmitter 310, and a receiver 312. As may beappreciated, the processor 302, the memory 304, the input device 306,the display 308, the transmitter 310, and the receiver 312 may besubstantially similar to the processor 202, the memory 204, the inputdevice 206, the display 208, the transmitter 210, and the receiver 212of the remote unit 102, respectively.

In various embodiments, the receiver 312 is used to receive informationfrom the remote unit 102 indicating a request for system information. Insome embodiments, the transmitter 310 may be used to transmit a feedbackresponse to the remote unit 102 indicating that the request for thesystem information was received. Although only one transmitter 310 andone receiver 312 are illustrated, the base unit 104 may have anysuitable number of transmitters 310 and receivers 312. The transmitter310 and the receiver 312 may be any suitable type of transmitters andreceivers. In one embodiment, the transmitter 310 and the receiver 312may be part of a transceiver.

FIG. 4 illustrates one embodiment of communications 400 for transmittingand receiving feedback for a system information request. Specifically,communications 400 between a UE 402 and a gNB 404 are illustrated. Thecommunications 400 may facilitate the UE 402 requesting on-demand SIBsusing a RACH message 3 based approach.

In certain embodiments, the gNB 404 may transmit a periodic broadcast406 to the UE 402. The periodic broadcast 406 may include minimum SIused by the UE 402 for communication. In various embodiments, the UE 402may transmit a PRACH preamble 408 to the gNB 404. In some embodiments,in response to transmitting the PRACH preamble 408, the gNB 404 maytransmit an UL grant in a random access response 410. After receivingthe random access response 410, the UE 402 may transmit a systeminformation (“SI”) request 412 to the gNB 404 that indicates on-demandSIBs requested by the UE 402. The system information request 412 may bea random access message 3. As may be appreciated, the on-demand SIBs maynot be broadcast (e.g., transmitted) unless requested. In response tothe system information request 412, the gNB 404 may transmit a feedbackresponse 414 that indicates that the system information request 412 wasreceived by the gNB 404.

In certain embodiments, because message 3 is a UL-SCH transmission(e.g., medium access control (“MAC”) protocol data unit (“PDU”)) moreinformation may be provided by the UE 402 within the message 3 than in aPRACH preamble. In one embodiment, the UE 402 includes a MAC controlelement (“CE”) within the RACH message 3 to convey the SI requestinformation. In such an embodiment, the MAC CE may contain a bitmapindicating the SI(s)/SIB(s) that the UE 402 wants to acquire. Moreover,the bitmap may have an entry for all on-demand SI(s)/SIB(s) (e.g., allSIBs not broadcast in the cell). Using the bitmap, the UE 402 mayindicate (e.g., by setting the corresponding field/bit to a predefinedvalue) which of the SI(s)/SIB(s) it wants to acquire. In certainembodiments, the UE 402 requests system information not only for thecurrent cell, (e.g., cell UE is camped on/connected with) but also forneighboring cells. In one embodiment, the UE 402 includes informationwithin the message 3 (e.g., SI request message) which indicates that thegNB 404 should provide to UE 402 all system information used in apredetermined area, covering one or multiple cells. In certainembodiments, the UE 402 may include an RRC message within the message 3to convey SI request information. In such an embodiment, the RRC messagemay contain the SI(s)/SIB(s) that the UE 402 wants to acquire.

In various embodiments, some SI may be related to the UE's 402capability and so indicating such capability might provide usefulinformation to the gNB 404 as to whether related SI information is to betransmitted to the UE 402 in response or not. In certain embodiments, toallow the gNB 404 to allocate sufficient uplink resources fortransmission of the SI-request bitmap MAC CE in message 3, one or morePRACH preambles may be used to indicate that the purpose of the RACHprocedure is for on-demand SI acquisition. In various embodiments, thesize of message 3 (e.g., the system information request 412) might bedifferent for an initial Access and an SI-request (e.g., message 3 foron-demand SI acquisition may only include the system information requestmessage, but no further information like an identity identifying the UEor some buffer status report). In certain embodiments the content of theRACH response message (e.g., RACH message 2), which is sent by gNB inresponse to receiving a PRACH preamble may be different for a RACHprocedure with the purpose for on-demand SI acquisition than for a RACHprocedure for another purpose. In some embodiments, because more thanone UE may send an identical reserved PRACH preambles for SI request, acollision of message 3 may occur (e.g., multiple UEs are sendingSI-request MAC CE (with different content) on UL resources allocated inRACH message 3). Accordingly, in certain embodiments,collision/contention resolution may be used to enable the UE 402 to knowwhether the transmitted SI request was received by gNB 404. In oneembodiment, the gNB 404 may send in RACH message 4 (e.g., the feedbackresponse 414) the SI-request bitmap MAC CE which it received in message3. This will enable the UE 402 to identify whether its SI-request wascorrectly received by the gNB 404. In various embodiments, the gNB 404could include the requested SIB(s)/SI(s) in the RACH message 4 as partof the feedback response 414 (e.g., RRC message). In some embodiments,upon reception of RACH message 4, the UE 402 may check, by decoding theMAC CE, whether the requested SIB(s)/SI(s) are included (e.g., checkingwhether the received MAC CE matches the SI-request MAC CE sent inmessage 3). In embodiments in which the MAC CE matches the SI-requestMAC CE, the SIB(s)/SI(s) may be delivered to the RRC. In embodiments inwhich the MAC CE does not match the request, the UE 402 may trigger theSI acquisitions procedure again (e.g., sending PRACH preamble forSI-request, retransmitting the message 3, etc.). Moreover, the UE 402may, upon transmission of message 3, monitor (e.g., during a certaintime window, during a predetermined period of time) for a RACH message4. In situations in which no RACH message 4 is received during thepredetermined period of time the UE 402 may trigger the SI acquisitionprocedure again (e.g., sending PRACH preamble for SI-request,retransmitting the message 3, etc.).

In various embodiments, the SIB(s)/SI(s) requested by the UE 402 may bebroadcast (instead of sending them in message 4). In such embodiments,the RACH message 4 may include the scheduling information whichindicates the timing information for the broadcast of the requestedSIB(s)/SI(s). Furthermore, in such embodiments, the UE 402 may not readminimum system information in order to acquire the timing informationbefore receiving the broadcasted SIB(s)/SI(s).

In various embodiments, SIB(s)/SI(s) requested by the UE 402 may bepartly provided by broadcast and partly within RACH message 4. In oneembodiment, the RACH message 4 may include information indicating whichSI(s)/SIB(s) are provided by RACH message 4 and which SI(s)/SIB(s) arebroadcast (e.g., the UE 402 monitors during the SI window associatedwith these SI(s)/SIB(s) for receiving the broadcast channel).

In one embodiment, the gNB 404 may send multiple RACH message 4 (e.g.,to be provided SI(s)/SIB(s) may not fit within only one downlinktransmission). In certain embodiments, an indication is contained withinthe RACH message 4 (e.g., SI feedback response) indicating whether theUE 402 should continue monitoring for further downlink transmissions(e.g., further RACH message 4 transmissions) for reception of furtherSI(s)/SIB(s) or whether UE may stop monitoring for further downlinktransmissions (e.g., further RACH message 4 transmissions). In oneembodiment, this indication is a boolean flag. In various embodiments,the RACH message 4 may include information indicating whether the UE402, in response to receiving the RACH message, should initiate an RRCconnection establishment procedure or an RRC connection resumeprocedure.

As may be appreciated, one advantage of including the SI-request bitmapMAC CE in message 4 is that collision/contention resolution may beperformed on the MAC level. In certain embodiments, the UE 402 may,after sending RACH message 3 and upon receiving a HARQ acknowledgment asthe feedback response 414, read the minimum SI and check whether the gNB404 indicates that the requested SIBs are in response to having receivedthe SI request broadcast in the cell. In such an embodiment, thecollision/contention resolution would happen at the minimum SI level.

In some embodiments, the radio network temporary identifier (“RNTI”)used for RACH message 4 transmission may indicate the on-demand SIB(s)which are either included in message 4 (e.g., RRC message) or beingbroadcast. In such embodiments, a certain number of RNTI(s) (e.g., fromthe cell RNTI (“C-RNTI”) space) may be reserved and associated to aspecific SIB or a combination of several SIB(s). Moreover, the UE 402may, upon transmission of message 3, monitor (e.g., during a certaintime window, during a predetermined period of time) for a PDCCHaddressed to one of those reserved RNTIs. Accordingly, depending on thereceived PDCCH/RNTI (e.g., the feedback response 414) the UE 402 may beaware of whether its SI request sent in message 3 was received by thegNB 404. In various embodiments, the RNTI used for RACH message 4 may bea common predefined RNTI value. In such embodiments, a common predefinedRNTI is used which is specific to the SI-request. Moreover, in suchembodiments, no temporary cell RNTI (“T-CRNTI”) needs to beallocated/signalled in the RACH response message. In embodiments inwhich a common RNTI is used, the RACH message 4 (e.g., SI feedbackmessage) may not only be addressed to a single UE but may be addressedto multiple UEs which sent a SI request. As such, each UE which sent aSI request may check based on the common RNTI, whether its request wasreceived by gNB 404. In embodiments in which a common RNTI is used forRACH message 4, the SI feedback message conveyed within RACH message 4may contain a bitmap which denotes the SIB(s) for which gNB 404 hasreceived a request (e.g., multiple requests from different UEs). Assuch, each UE which sent a SI request may check, based on the receivedbitmap, whether its request was received by the gNB 404. In certainembodiments, UEs which have not sent an SI request may monitor for thecommon RNTI in order to receive the SI feedback message (e.g., RACHmessage 4) and check the requested SIB(s) so that a UE may not need torequest SIB(s) which have been already requested by other UEs.

In certain embodiments described herein, the RACH procedure may be usedfor the sole purpose of requesting on-demand SI. However, in someembodiments, the UE 402 may establish an RRC connection and at the samerequest on-demand SI, or the UE 402 in an inactive state may transmit ULdata and at the same time trigger an on-demand SI acquisition procedure.In such embodiments, which are just examples, the UE 402 may send theSI-request MAC CE and the RRC connection request message in RACH message3, or SI-request MAC CE and UL data and potentially some buffer statusreport (“BSR”) MAC CE in RACH message 3. In such embodiments, the gNB404 may distinguish between the different cases (e.g., SI-request,SI-Request plus initial access, SI-request plus UL data) so that the gNB404 may dimension the size of the UL grant accordingly. Accordingly, insome embodiments, PRACH preambles may be reserved for identification ofthe different cases.

FIG. 5 illustrates another embodiment of communications 500 fortransmitting and receiving feedback for a system information request.Specifically, communications 500 between a UE 502 and a gNB 504 areillustrated. The communications 500 may facilitate the UE 502 requestingon-demand SIBs using a RACH message 1 based approach.

In certain embodiments, the gNB 504 may transmit a periodic broadcast506 to the UE 502. The periodic broadcast 506 may include minimum SIused by the UE 502 for communication. In various embodiments, the UE 502may transmit a PRACH preamble 508 to the gNB 504. The PRACH preamble 508indicates an SI request to the gNB 504 that indicates on-demand SIBsrequested by the UE 502. The PRACH preamble 508 may be a message 1. Asmay be appreciated, the on-demand SIBs may not be broadcast (e.g.,transmitted) unless requested. In response to the PRACH preamble 508,the gNB 504 may transmit a feedback response 510 that indicates that thePRACH preamble 508 was received by the gNB 504.

In certain embodiments, the PRACH preamble 508 is resource specific toan SIB or set of SIBs which the UE 502 wants to obtain. In someembodiments, the PRACH preamble 508 that is resource specific to eachSIB or set of SIBs are reserved and indicated in periodicallybroadcasted minimum SI. In certain embodiments, the UE 502 may requestsystem information not only for the current cell, (e.g., cell UE iscamped on/connected with) but also for neighboring cells. In oneembodiment, a PRACH preamble 508 indicates that the gNB 504 shouldprovide to UE 502 all system information used in a predetermined area,covering one or multiple cells.

Upon transmission of the PRACH preamble 508 (e.g., the SI requestpreamble), the UE 502 may monitor for a feedback message (e.g., thefeedback response 510) sent from the gNB 504. The UE 502 may monitor forthe feedback message during a defined time period (e.g., time window).Upon reception of the feedback message the UE 502 may monitor during asignaled SI window for the requested SI (e.g., as indicated in thescheduling information broadcast in the minimum SI).

In the absence of the feedback message, the UE 502 may assume that thePRACH transmission was not detected by the gNB 504 and may, in certainembodiments, retransmit the PRACH preamble 508 (e.g., SI request). Insome embodiments, retransmission of the PRACH preamble 508 may be withan increased transmission power. In various embodiments, a counter isused and is initially set to zero and increased for each PRACH preamble508 transmission. In certain embodiments, there may be a maximum numberof PRACH preamble 508 transmission attempts defined. In someembodiments, if the maximum number of PRACH preamble 508 transmissionattempts is reached the UE 502 may indicate to a higher layer a randomaccess problem (e.g., radio link failure procedure might be started suchas for an inactive mode).

In some embodiments, a new physical layer (“PHY”) signal may be used toconvey the feedback message. In various embodiments, the feedbackmessage itself may include a PRACH preamble identifier field identifyingthe detected PRACH Preamble 508. In certain embodiments, DCI (e.g.,PDCCH) may contain the PRACH preamble 508 ID that was detected by thegNB 504. In one embodiment, a DCI format used for scheduling a downlinkdata transmission (e.g., format 1A) may be used to transmit the feedbackfor a received SI request. In some embodiments, a new RNTI value (e.g.,SI-Request RNTI) may be used to indicate that the DCI (e.g., PDCCH)contains the SI request feedback message. This may enable the UE 502 todistinguish between a random access response message (e.g., cyclicredundancy check (“CRC”) scrambled with random access RNTI (“RA-RNTI”))and the SI-request feedback message (e.g., CRC of PDCCH scrambled withSI-request RNTI). In various embodiments, because no corresponding PDSCHis transmitted (e.g., only PDCCH (DCI)) the DCI itself may contain thePRACH preamble (or an indicator identifying the PRACH preamble 508). Incertain embodiments, instead of signaling a detected PRACH preamble 508ID, the gNB 504 may signal a list of detected PRACH preamble IDs,including the PRACH preambles detected from other UEs. The feedbackmessage may be a common feedback message reflecting the status ofreceived SI requests/PRACH preambles. Accordingly, in such embodiments,the UE 502 may check whether its SI request/SI PRACH preamble wasreceived by the gNB 504. Furthermore, this feedback message may alsoindicate which SIB(s) the gNB 504 will provide (subsequently) (e.g., bybroadcast). In some embodiments, the feedback message (DCI) may containa bitmap indicating the SIB(s) for which a request was received andwhich will be provided by broadcast/unicast accordingly.

In various embodiments, the UE 502 may receive a request to perform therandom access procedure for a different purpose than for on-demand SIacquisition (e.g., initial access) while also being triggered to performthe SI acquisition. In such embodiments, the UE 502 may deprioritize theRACH procedure for SI request. For example, the UE 502 may first performthe initial access and then retrieve the system information by dedicatedsignaling (e.g., RRC signaling).

In some embodiments, the SI-request feedback message may be transmittedby means of a PDCCH scrambled with an RA-RNTI (e.g., RACH response). Insuch embodiments, a predefined value(s) of a field or a combination offields within the DCI may indicate whether the DCI is used for a normalRACH response or as an SI-request feedback message.

In various embodiments, no PDSCH is necessary to transmit a feedbackmessage (e.g., the feedback is contained in the DCI/PDCCH). In suchembodiments, the feedback may be a single PRACH preamble ID, a list ofPRACH preamble IDs, a bitmap indicating the requested SIB(s) which willbe provided by broadcast. In some embodiments, the RA-RNTI value may bea reserved RA-RNTI value (e.g., not calculated from the time/resource inwhich the preamble was sent). In such embodiments, the RA-RNTI may bededicated/specific to the SI request.

In various embodiments, the SI-request feedback is transmitted withinthe RACH response message transmitted on a PDSCH (e.g., MAC PDU). Insome embodiments, the UE 502 monitors upon transmission of the PRACHpreamble 508 during the RACH response window for the RACH responsemessage (e.g., PDCCH addressed to RA-RNTI calculated from thetime/resource in which preamble was sent). In such embodiments, the RACHresponse message may be a MAC PDU which consists of a MAC header andcorresponding MAC random access responses (“MAC RAR”). In someembodiments, the MAC PDU header includes one or more MAC PDU subheaders.Furthermore, each subheader corresponds to a MAC RAR (e.g., except forthe backoff indicator subheader). In one embodiment, the MAC PDUsubheader for a RAR contains the PRACH preamble 508 ID field identifyingthe transmitted random access. In certain embodiments, the RAR messageitself includes the following information: Temporary C-RNTI: the gNB 504gives another identity to the UE 502 which is called temporary C-RNTIfor further communication; Timing Advance Value: the gNB 504 informs theUE 502 to change its timing so it can compensate for the round tripdelay caused by UE distance from the gNB 504; and/or Uplink GrantResource: the gNB 504 may assign initial resources to the UE 502 so thatit may use UL-SCH.

In certain embodiments, for an SI-request the UE 502 may only need toreceive confirmation that the PRACH preamble 508 was detected by the gNB504. In such embodiments, there may be no consecutive UL-SCHtransmission (e.g., message 3) in reponse to the reception of the SIrequest feedback message. Accordingly, in such embodiments only a MACPDU subheader for a RAR containing the the PRACH preamble 508 ID fieldidentifying the received PRACH preamble 508 or list of received PRACHpreambles is transmitted (e.g., no associated RAR message carrying ULgrant, T-CRNTI, TA, etc.).

In some embodiments, the SI-request feedback may be transmitted withinthe RACH response message transmitted on a PDSCH (e.g., MAC PDU). Insuch embodiments, the feedback which is transmitted within the RACHresponse may be a list of PRACH preamble 508 IDs (e.g., identifying allSI request preambles received by gNB), a bitmap, or another indicationof the requested SIB(s) which will be provided by gNB. In variousembodiments, a new MAC CE may be introduced which contains either abitmap or a list of the SIB(s) for which gNB received requests. In someembodiments, a reserved RA-RNTI value may be used (e.g., not calculatedfrom the time/resource in which the preamble was sent). This reservedRA-RNTI may be specific to the on-demand SI request.

In various embodiments, the UE 502 may send a PRACH preamble 508 andread minimum SI (e.g., SIB1) in order to check whether the gNB 504 willbroadcast the requested SI (e.g., a broadcast/not broadcast indicatormay be flipped by the gNB 504 in response to the preamble beingdetected). In such embodiments, if the minimum SI doesn't indicate thatthe requested SI is broadcast, the UE 502 may retrigger the SI requestprocedure (e.g., send the PRACH preamble 508. In such embodiments, thefeedback is given by the minimum SI.

In various embodiments, scheduling information for the transmission of arequested on-demand SI/SIB may be transmitted together with theSI-request feedback message. In such embodiments, the schedulinginformation may denote timing information when the UE 502 should monitorfor the requested on-demand SI. In various embodiments, the schedulinginformation for on-demand SI is provided by minimum SI (e.g., in SIB1,including SIB type, validity information, periodicity, SI-windowinformation). In certain embodiments, when transmitting scheduling infofor requested on-demand SI together with the SI feedback message, thegNB 504 may have more flexibility for the transmission of the requestedSI. In some embodiments, the requested SI could be transmitted at anearlier time instance compared to the timing info provided by minimum SI(e.g., reduced latency for acquisition of system information). Also inembodiments that include the scheduling information in the same messageas the feedback message, the UE 502 doesn't need to read the minimum SIin order to acquire the latest (up-to-date) scheduling info for theon-demand SI. In one embodiment, the scheduling information for therequested SI is carried within an RAR message. Specifically, in such anembodiment, the MAC RAR is associated with a MAC PDU subheader having arandom access preamble identity (“RAPID”) identifying a transmittedPRACH preamble 508 (e.g., SI-request feedback) and carries thescheduling information for the transmission of the requested on-demandSI. In embodiments in which the feedback message includes the schedulinginformation, the UE 502 may follow this scheduling information forreception of the requested SI. In such embodiments, the schedulinginformation provided within the feedback message may take precedenceover the scheduling information provided by minimum SI. In variousembodiments, when scheduling information for on-demand SI is alwaysprovided together with the feedback message, there may be no need tobroadcast the scheduling information within minimum SI, which would inturn save signaling overhead.

FIG. 6 is a schematic flow chart diagram illustrating one embodiment ofa method 600 for receiving feedback for a system information request. Insome embodiments, the method 600 is performed by an apparatus, such asthe remote unit 102. In certain embodiments, the method 600 may beperformed by a processor executing program code, for example, amicrocontroller, a microprocessor, a CPU, a GPU, an auxiliary processingunit, a FPGA, or the like.

The method 600 may include transmitting 602 information indicating arequest for system information. The method 600 also includes monitoring604, during a predetermined time period, for a feedback responseindicating that the request for the system information was received.

In one embodiment, the method 600 includes receiving schedulinginformation corresponding to the system information. In a furtherembodiment, the method 600 includes, in response to receiving thefeedback response, receiving the system information based on thescheduling information. In certain embodiments, the method 600 includes,in response to not receiving the feedback response: retransmittinginformation indicating the request for the system information; and themonitoring, during the predetermined time period, for the feedbackresponse indicating that the request for the system information wasreceived. In various embodiments, retransmitting the informationindicating the request for the system information includesretransmitting the information using increased power. In someembodiments, retransmitting the information indicating the request forthe system information includes retransmitting information indicatingthe request for the system information up to a predetermined number oftimes.

In certain embodiments, the feedback response is part of downlinkcontrol information. In some embodiments, a radio network temporaryidentifier is used to indicate the feedback response. In variousembodiments, the feedback response is indicated by one or more fields ofdownlink control information set to one or more predefined values. Inone embodiment, the feedback response is part of a random accessresponse message transmitted on a physical downlink shared channel. Incertain embodiments, the information indicating the request for thesystem information includes a physical random access channel preamble.

In some embodiments, the feedback response includes a physical randomaccess channel preamble identifier corresponding to the physical randomaccess channel preamble. In various embodiments, the informationindicating the request for the system information is part of a message 3transmission during random access. In certain embodiments, theinformation indicating the request for the system information includes abitmap indicating the requested system information. In one embodiment,the feedback response includes information indicating the requestedsystem information. In some embodiments, the feedback response is partof a contention resolution message during random access. In variousembodiments, downlink scheduling information for the system informationis transmitted with the feedback response.

FIG. 7 is a schematic flow chart diagram illustrating a furtherembodiment of a method 700 for transmitting feedback for a systeminformation request. In some embodiments, the method 700 is performed byan apparatus, such as the base unit 104. In certain embodiments, themethod 700 may be performed by a processor executing program code, forexample, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliaryprocessing unit, a FPGA, or the like.

The method 700 may include receiving 702 information indicating arequest for system information. The method 700 also includestransmitting 704 a feedback response indicating that the request for thesystem information was received.

In one embodiment, the method 700 includes transmitting schedulinginformation corresponding to the system information. In a furtherembodiment, the method 700 includes transmitting the system informationbased on the scheduling information.

In certain embodiments, the feedback response is part of downlinkcontrol information. In some embodiments, a radio network temporaryidentifier is used to indicate the feedback response. In variousembodiments, the feedback response is indicated by one or more fields ofdownlink control information set to one or more predefined values. Inone embodiment, the feedback response is part of a random accessresponse message transmitted on a physical downlink shared channel. Incertain embodiments, the information indicating the request for thesystem information includes a physical random access channel preamble.

In some embodiments, the feedback response includes a physical randomaccess channel preamble identifier corresponding to the physical randomaccess channel preamble. In various embodiments, the informationindicating the request for the system information is part of a message 3transmission during random access. In certain embodiments, theinformation indicating the request for the system information includes abitmap indicating the requested system information. In one embodiment,the feedback response includes information indicating the requestedsystem information. In some embodiments, the feedback response is partof a contention resolution message during random access. In variousembodiments, downlink scheduling information for the system informationis transmitted with the feedback response.

Embodiments may be practiced in other specific forms. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

1. An apparatus comprising: a transmitter that transmits informationindicating a request for system information, wherein the informationindicating the request for the system information comprises a bitmapindicating the system information requested; and a processor thatmonitors, during a predetermined time period, for a feedback responseindicating that the request for the system information was received,wherein the feedback response is part of a contention resolution messagereceived during a random access procedure.
 2. The apparatus of claim 1,further comprising a receiver that: receives scheduling informationcorresponding to the system information; and in response to receivingthe feedback response, receives the system information based on thescheduling information.
 3. The apparatus of claim 1, wherein, inresponse to not receiving the feedback response: the transmitterretransmits the information indicating the request for the systeminformation; and the processor monitors, during the predetermined timeperiod, for the feedback response indicating that the request for thesystem information was received.
 4. The apparatus of claim 3, whereinthe transmitter retransmits the information using increased power. 5.The apparatus of claim 3, wherein the transmitter repeats retransmittinginformation indicating the request for the system information up to apredetermined number of times.
 6. The apparatus of claim 1, wherein thefeedback response is part of downlink control information.
 7. Theapparatus of claim 1, wherein a radio network temporary identifier isused to indicate the feedback response.
 8. The apparatus of claim 1,wherein the feedback response is indicated by one or more fields ofdownlink control information set to one or more predefined values. 9.The apparatus of claim 1, wherein the feedback response is part of arandom access response message transmitted on a physical downlink sharedchannel.
 10. The apparatus of claim 1, wherein the informationindicating the request for the system information comprises a physicalrandom access channel preamble, and the feedback response comprises aphysical random access channel preamble identifier corresponding to thephysical random access channel preamble.
 11. The apparatus of claim 1,wherein downlink scheduling information for the system information istransmitted with the feedback response.
 12. A method comprising:transmitting information indicating a request for system information,wherein the information indicating the request for the systeminformation comprises a bitmap indicating the system informationrequested; and monitoring, during a predetermined time period, for afeedback response indicating that the request for the system informationwas received, wherein the feedback response is part of a contentionresolution message received during a random access procedure.
 13. Anapparatus comprising: a receiver that receives information indicating arequest for system information, wherein the information indicating therequest for the system information comprises a bitmap indicating thesystem information requested; and a transmitter that transmits afeedback response indicating that the request for the system informationwas received, wherein the feedback response is part of a contentionresolution message transmitted during a random access procedure.
 14. Theapparatus of claim 13, wherein the transmitter: transmits schedulinginformation corresponding to the system information; and transmits thesystem information based on the scheduling information.
 15. Theapparatus of claim 13, wherein the feedback response is part of downlinkcontrol information.
 16. The apparatus of claim 13, wherein a radionetwork temporary identifier is used to indicate the feedback response.17. The apparatus of claim 13, wherein the feedback response isindicated by one or more fields of downlink control information set toone or more predefined values.
 18. The apparatus of claim 13, whereinthe feedback response is part of a random access response messagetransmitted on a physical downlink shared channel.
 19. The apparatus ofclaim 13, wherein the information indicating the request for the systeminformation comprises a physical random access channel preamble, and thefeedback response comprises a physical random access channel preambleidentifier corresponding to the physical random access channel preamble.20. The apparatus of claim 13, wherein downlink scheduling informationfor the system information is transmitted with the feedback response.21. A method comprising: receiving information indicating a request forsystem information, wherein the information indicating the request forthe system information comprises a bitmap indicating the systeminformation requested; and transmitting a feedback response indicatingthat the request for the system information was received, wherein thefeedback response is part of a contention resolution message transmittedduring a random access procedure.